1 Office of Public Health, State Department of Health, 79 Elm Street, Hartford, Connecticut 06115
Dr. H. H. Neumann's paper on "PicaSymptom or Vestigial Instinct?" (Pediatrics, 46:441) raised two separate questions. I subscribe to the first question and hypothesis: (1) Chewing on hard material may be a deterrent against cavities. This discovery alone may turn out to be the answer to one of the oldest health problems and a great contribution to preventive medicine.
On the second question I strongly disagree with Dr. Neumann: (2) Can pica be explained solely and/or primarily on the basis of vestigial instinct? I believe that Dr. Neumann does not distinguish deviant behavior such as pica (not necessarily a chewing activity but rather the ingestion of a variety of always unedible materials) from the healthy habit of "chewing" on hard material (with or without ingestion but I suspect more without than with).